Apr. 15. 1914 
Coloration of Seed Coat of Cowpeas 
35 
(fig. 1, a). Beneath this is a second layer, a single cell deep. Its cells 
are relatively cubical and have thick walls, but one horizontal diameter 
is slightly longer than the other. They are described by some authors 
as of hour-glass shape, a rather fanciful resemblance. They may be 
Fig. i.—T ransverse section of the seed coat of a cowpea with the cells expanded with chloral hydrate 
so as to show the structure of the three layers: cm. Cuticle; a , palisade layer; b, middle or hour-glass 
layer; c, basal-color layer. 
said to lie at right angles to those of the palisade layer (fig. 1,6). Beneath 
this second layer is a comparatively thick layer from 10 to 20 cells deep, 
the cells being larger than those of the second layer and with relatively 
thin walls. These also lie parallel to the surface—that is, are hori- 
